Fractional Fourier Transform (FRFT) contains simultaneity the time-frequency information of the signal, and it is considered a new tool for time-frequency analysis. The energy distribution of image is analyzed and simulated in this paper, the characteristic of the amplitude and phase is extracted in Fractional Fourier domain of an image. The simulation results show that the FRFT can represent t...

In this paper, the mechanical behaviors of bridges with unseating prevention devices in the superstructure were investigated. These devices can prevent bridge from unseating and divert most of the seismic forces from transferring to the bridge columns. The models of the rubber bearing, restrainer, and shear key were proposed and implemented into the SAP 2000 to obtain the seismic response of th...

The laser Doppler flowmetry (LDF) technique is a non invasive method that measures the microvascular blood cell perfusion through tissue. It uses the principle of Doppler shifts. LDF signals are non stationary. As other physiological signals, the LDF ones need an appropriate method to be analyzed and the extraction of the microvascular activities dynamic evolution is not an easy task. For that ...

It is shown how the Zak transform can be used to find nontrivial examples of functions f, g E L 2 ( 2 ) with f . g = 0 = F . C, where F, G are the Fourier transforms of f, g, respectively. This is then used to exhibit a nontrivial pair of functions h, keL2(T1), h # k, such that I h I = 1 k 1 , I H I = I K 1 . A similar construction is used to find an abundance of nontrivial pairs of functions h...

In this paper, an overview of the stochastic modeling for analysis/synthesis of noisy sounds is presented. In particular, we focused on the time-frequency domain synthesis based on the inverse fast Fourier transform (IFFT) algorithm from which we proposed the design of a spatialized synthesizer. The originality of this synthesizer remains in its one-stage architecture that efficiently combines ...

The ridges of the wavelet transform, the Gabor transform or any time-frequency representation of a signal contain crucial information on the characteristics of the signal. Indeed they mark the regions of the time-frequency plane where the signal concentrates most of its energy. We introduce a new algorithm to detect and identify these ridges. The procedure is based on an original penalization o...

In the continuous-time domain, Maximum-Likelihood (ML) detection of a chirp signal in white Gaussian noise can be done via the line-integral transform of the classical Wigner distribution. The line-integral transform is known variously as the Hough transform and the Radon transform. For discrete-time signals, the Wigner-type distribution defined by Claasen and Mecklenbrauker has become popular ...